Phyllode is a modification of :

Options

A. root
B. stem
C. petiole
D. flower

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the modification known as "phyllode." We need to identify what part of the plant it is a modification of.

2. **Identifying Options**: The options provided are:
- A) Root
- B) Stem
- C) Petiole
- D) Leaf

3. **Definition of Petiole**: The petiole is the stalk that attaches the leaf blade (lamina) to the stem. It is also known as mesopodium. Its primary function is to elevate the leaf blade above the stem to maximize light exposure for photosynthesis.

4. **Modification of Petiole**: A phyllode is a specific type of modification of the petiole. In this modification, the petiole becomes flattened and takes on a leaf-like appearance, allowing it to perform photosynthesis.

5. **Function of Phyllode**: The phyllode serves the function of the leaf lamina in plants that have adapted to xerophytic (dry) conditions. This adaptation helps reduce transpiration and allows the plant to survive in arid environments.

6. **Conclusion**: Based on the explanation, we conclude that a phyllode is a modification of the petiole.

### Final Answer:
Phyllode is a modification of **C) Petiole**.

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